Fruits of Chinese wingnut Pterocarya stenoptera have two wings and are dispersed by wind. To know the effects of wing shape on seed dispersal ability of this species, the relationship between wing shape and falling speed of the fruits was studied. Wing shape variation was characterized using principal component analysis of elliptic Fourier descriptors, and an experiment that the fruits were dropped from height of 9.5 m was conducted. Falling speed of the fruits was positively correlated with the square root of wing loading and negatively correlated with a principal component that represented the angle between two wings. Therefore, it is thought that seed dispersal ability of this species is affected by wing shape, not only by wing area and fruit weight.